Anesthesia and analgesia
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Anesthesia and analgesia · Feb 2005
Randomized Controlled Trial Clinical TrialSpinal 2-chloroprocaine: the effect of added clonidine.
Preservative-free 2-chloroprocaine (2-CP) is being investigated for short-acting spinal anesthesia. Clonidine improves the quality of spinal bupivacaine and ropivacaine, but in traditional doses (1-2 microg/kg) it produces systemic side effects. It has not been studied in combination with 2-CP. ⋯ Clonidine increased tourniquet tolerance from 33 to 45 min (P = 0.06) and increased time to ambulation, spontaneous voiding, and discharge (99 +/- 18 min versus 131 +/- 15 min for all; P = 0.001). There were no differences in hemodynamic measurements, and no subject reported transient neurologic symptoms. We conclude that small-dose clonidine increases the duration and improves the quality of 2-CP spinal anesthesia without systemic side effects.
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Anesthesia and analgesia · Feb 2005
Randomized Controlled Trial Clinical TrialThe effect of propofol on thermal pain perception.
We studied the effect of propofol, a widely used sedative-hypnotic drug, on pain perception. Eighteen subjects received propofol in two sedative concentrations that were balanced and randomized in order. Painful (45 degrees C, 47 degrees C, and 49 degrees C) stimulation temperatures were presented in random order, and nonpainful 31 degrees C stimuli were presented on alternate trials. ⋯ Pain unpleasantness was 23/100 for placebo, 29/100 for mild, and 33/100 for moderate sedation. This effect was unexpected and may be explained by a difference of subjective pain experience by a patient and the perceived level of analgesia by a health care provider in sedated patients. This finding calls further attention to the need for adequate analgesia in patients sedated with propofol.
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Anesthesia and analgesia · Feb 2005
Large concentrations of nitrous oxide decrease the isoflurane minimum alveolar concentration sparing effect of morphine in the rat.
Many adjuvant drugs have demonstrated anesthetic-sparing properties when combined with volatile anesthetics. Nitrous oxide is combined with volatile anesthetics to reduce the concentrations of volatile anesthetics required to produce anesthesia. Analgesic doses of opioids clearly reduce the requirement for inhaled anesthetics in both human patients and experimental animals. ⋯ The administration of morphine reduced the MAC(ISO) when used with 0% or 30% nitrous oxide. This MAC(ISO) by morphine reduction was less with 50% nitrous oxide and nonexistent at 70% nitrous oxide. However, with morphine present the MAC(ISO) was independent of the nitrous oxide concentration in the 30%-70% range.